Valve systems are used to control the flow of powdered or granular materials from sealed containers within closed loop material feed systems. Such valve systems may include first and second components that are rotatable relative to each other to open and close a valve assembly. While existing valve systems may perform well under some conditions, operation may be challenging depending upon the characteristics of the materials or substances within the containers. Accordingly, an improved valve system for use with a variety of materials or substances would be desirable.